The present invention relates to microfluidic devices, particularly to sample preparation and detection devices, and more particularly to a sample preparation and analysis to which may incorporate both immunoassays and PCR assays in one compact, field-portable microchip.
Microfluidic systems are becoming increasingly popular as a way to integrate sample preparation and biological assays on a single substrate. The resulting reduction in manual operations and reduced reagent use can lead to significant cost savings in performing biological tests.
Whether in defense of bioterrorists or checking a blood sample of a potential victim, there is a need for field-portable biodetectors. Many microfluidic chips have been proposed for PCR/DNA analysis and for immunoassays. However, there is no known approach that incorporates both types of diagnostics on a single chip. The ability to perform multiple diagnostics on a single substrate is important in many counter biological warfare applications to reduce the rate of false positives. Current commercial microdevices concentrate on the assay over the sample preparation because the expected user is usually a highly skilled laboratory technician.
The present invention involves a single biochip having the capability of performing both immunoassays and PCR assays. This feature is important when a device needs to run multiple inexpensive, specific tests. The immunoassays are relatively inexpensive for use in multiple tests and yet often inaccurate, while PCR tests can be very specific and can be used to verify the results of the immunoassay. The immunoassays can be run in true continuous mode with the device of the present invention; the device can be monitoring a significant amount of fluid continuously checking for a positive signal; and the overall sensitivity of the device can be orders of magnitude greater than other microdevices.
It is an object of the present invention to provide for sample preparation and analysis in one field-portable microchip.
A further object of the invention is to provide for both immunoassays and PCR assays in one compact, field-portable microchip.
Another object of the invention is to provide a fluidic microchip having capabilities for fluid and particle control with or without moving parts.
Another object of the invention is to provide a sample preparation and analysis tool that can operate in a true continuous mode.
Another object of the invention is to provide a field-portable microchip for sample preparation and analysis which includes micro-pumps, such as magnetohydrodynamic pumps, acoustic mixing and fractionation, dielectrophoretic sample concentration and purification, and on-chip optical detection capabilities.
Other objects and advantages of the present invention will become apparent from the following description and accompanying drawings. Basically, the present invention comprises a sample preparation and detection device for applications such as detecting the presence of pathogens in a bio-terrorist event or to sample blood for the presence of infectious agents. The sample preparation and analysis device can be located in one compact, field-portable microchip. The device of this invention is incorporates both immunoassays and PCR assays, can have no moving parts, and can operate in a continuous mode. The single microchip, for example may contain no moving parts and include a micro-pumps, such as magnetohydrodynamic (MHD) pumps to move the fluid through the system, acoustic mixing and fractionation, dielectrophoretic (DEP) sample concentration and purification, and have on-chip optical detection capabilities, thereby providing inexpensive and robust instrumentation. Unlike other devices such as capillary electrophersis which require that all sample be introduced in a small volume at a single time for analysis, the device of the present invention can continuously monitor a fluid volume checking for a positive signal. The device is also capable of concentrating the sample into a smaller volume, inherently increasing the sample concentration and improving the overall sensitivity of the microdevice over those only capable of fluid handling. In this way, the overall sensitivity of the device can be greater than any known microdevice.